This invention relates in general to body and frame assemblies for vehicles. More specifically, this invention relates to an improved structure for an open channel side rail section for use in such a vehicular body and frame assembly.
Many land vehicles in common use, such as automobiles, vans, and tucks, include a body and frame assembly that is supported upon a plurality of ground-engaging wheels by a resilient suspension system, The structures of known body and frame assemblies can be divided into two general categories, namely, separate and unitized. In a typical separate body and frame assembly, the structural components of the body portion and the frame portion are separate and independent from one another When assembled, the frame portion of the assembly is resiliently supported upon the vehicle wheels by the suspension system and serves as a platform upon which the body portion of the assembly and other components of the vehicle can be mounted. Separate body and frame assemblies of this general type are found in most older vehicles, but remain in common use today for many relatively large or specialized use modern vehicles, such as large vans, sport utility vehicles, and trucks. In a typical unitized body and frame assembly, the structural components of the body portion and the frame portion are combined into an integral unit that is resiliently supported upon the vehicle wheels by the suspension system. Unitized body and frame assemblies of this general type are found in many relatively small modern vehicles, such as automobiles and minivans.
One well known example of a separate type of vehicular body and frame assembly is commonly referred to as a ladder frame assembly. A ladder frame assembly includes a pair of longitudinally extending side rails that are joined together by a plurality of transversely extending cross members. The cross members connect the two side rails together and provide desirable lateral, vertical, and torsional stiffness to the ladder frame assembly. The cross members can also be used to provide support for various components of the vehicle. Depending upon the overall length of the vehicle and other factors, the side rails of a conventional ladder frame assembly may be formed either from a single, relatively long structural member or from a plurality of individual, relatively short structural sections that are secured together. For example, in vehicles having a relatively short overall length, it is known to form each of the side rails from a single integral structural member that extends the entire length of the vehicle body and frame assembly. In vehicles having a relatively long overall length, it is known to form each of the side rails from two or more individual structural sections that are secured together, such as by welding, to provide a unitary structural member that extends the entire length of the vehicle body and frame assembly.
Traditionally, the side rails of known vehicle body and frame assemblies have been formed from open channel structural members, i.e., structural members that have a non-continuous cross sectional shape. In one known open channel structure, the side rail includes a vertically extending web portion having upper and lower flange portions extending horizontally therefrom. This structure is referred to as an open C-shaped structural member. It is relatively easy to secure cross members to side rails formed from open C-shaped structural members because flange portions of the cross members can lay flat against corresponding portions of the upper and lower flange portions. Thus, the flange portions of the cross member can be easily secured to the flange portions of the side rail in any conventional manner, such as by welding, rivets, bolts, and the like.
In another known open channel structure, the side rail includes a vertically extending web portion having upper and lower flange portions extending horizontally therefrom as described above, but further includes upper and lower lip portions that extend vertically inwardly from the edges of the upper and lower flange portions. This structure is referred to as a closed C-shaped structural member. The torsional stiffness of closed C-shaped structural members is desirably higher than the torsional stiffness of open C-shaped structural members. However, it has been found more difficult to secure cross members to closed C-shaped structural members than to open C-shaped structural members. This is because the inwardly extending lip portions of the closed C-shaped structural members prevent the flange portions of the cross member from laying flat against corresponding portions of the upper and lower flange portions. To address this, it is known to form one or more notches in the lip portions to permit the flange portions of the cross member to extend therethrough to the flange portions of the side rail. However, the formation of such notches weakens the side rail and reduces the torsional stiffness thereof. Thus, it would be desirable to provide an improved structure for an open channel side rail section for use in a vehicular body and frame assembly that facilitates the direct connection of a cross member to the upper and lower flanges thereof, yet which maintains a desired torsional stiffness.
This invention relates to an improved structure for an open channel side rail section for use in a vehicular body and frame assembly that facilitates the direct connection of a cross member to the upper and lower flanges thereof, yet which maintains a desired torsional stiffness. The side rail has a generally open C-shaped cross section defined by a vertically extending web, upper and lower flanges extending from the edges of the web, and upper and lower lips extending from the edge of the upper and lower flanges, respectively. The upper lip extends from the edge of the upper flange and is folded such that a portion of the upper lip is parallel to and abuts an inwardly facing surface of the upper flange. Similarly, the lower lip extends from the edge of the lower flange and is folded such that a portion of the lower lip is parallel to and abuts an inwardly facing surface of the lower flange. The horizontal positioning of the upper and lower lips provide for an increase in the structural strength of the side rail, while permitting a cross member to be positioned between and adjacent to both the upper and lower lips. The cross member can then be attached to the side rail by riveting the cross member to the upper and lower flanges. The upper and lower lips provide for a double gauge thickness of the sheet used to form the side rail in the riveted region where the cross member is attached to the side rail. The side rail can be formed with the upper and lower lips extending along the entire length of the side rail, or with a plurality of cooperating upper and lower lip segments. In another embodiment, the lips have vertically extending portions which abut the inwardly facing surface of the web. The free edges of the vertically extending portions can be formed so as to be adjacent to each other and connected together, such as by a weld.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.